Field of the Invention
The present invention relates to a shift control apparatus of an automatic transmission, and more particularly, to a shift control apparatus and a shift control method of an automatic transmission capable of determining a shift gear stage based on driver's demand acceleration.
Description of Related Art
Generally, a vehicle is provided with a transmission which receives power generated from an engine to control a vehicle speed. The transmission is classified into a manual transmission which is controlled by a driver and an automatic transmission which is automatically controlled based on a vehicle speed.
The automatic transmission controls hydraulic pressure by operating at least one solenoid valve according to a driving state, such as a vehicle speed and a throttle opening, in order to perform shifting to a target gear stage.
The typical method for determining a gear stage based on shift pattern regarding a vehicle speed and a position of an accelerator pedal performs upshifting and downshifting depending on the position of the accelerator pedal when a current vehicle speed is determined. In the case of an engine torque control, when an engine controller determines a torque map, a target engine torque is determined and an engine torque is transferred from engine to a flywheel to be an input torque of the transmission.
However, according to the related art, time is delayed due to oil pressure delay and a clutch control during a process of determining a gear stage of the transmission and as a multi-stage transmission over 10 stages is developed, the number of lines to be expressed by a shift pattern is increased.
Actually, in addition to setting the lines of the shift pattern, in the case of the transmission hydraulic control, factors to be mapped with each of the lines are exponentially increased, and as a result time consumption for the mapping and a burden on check points are increasing.
Further, the method for determining a gear stage based on the shift pattern according to the related art is short of satisfying a driver's demand acceleration. Therefore, to cope with the above problem, another shift pattern map dividing a driving mode into a sport mode, a normal mode, and the like depending on a driver's driving tendency is additionally set.
Further, the related art configures additional shift patterns such as an uphill pattern and a downhill pattern depending on a road gradient condition and therefore has a complicated process of determining a gear stage.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.